Hi - I'm hoping to find a short story published in the Alfred Hitchcock MysteryMagazine between 1976 and 1979 that had to do witha lady who was driving through a Forest Preserve and picked upa hitchhiker who was a man dressed as an old lady. Therehad been some murders in the area. A motorcyclistran into them, but it wasn't apparent if he was working alongside the hitchhiker.

I don't have a title or an author to go by.

Would anyone be able to help me in tracking down the particulars of this story?